The present invention relates to an apparatus for burning fuels. More specifically the present invention relates to an apparatus for reducing non-gaseous pollutants in the burning of fuels. Still more specifically, the present invention relates to an apparatus for reducing non-gaseous pollutants in the burning of low volatility fuels.
In the burning of heavy hydrocarbon fuels, having volatilities lower than that of automotive gasoline, a serious and continuing problem is the relatively high content of non-gaseous pollutants, such as carbon, unburned fuel and partially burned fuel, in the flue and exhaust gases. This of course has led the U.S. Environmental Protection Agency (EPA) to set standards limiting the quantity of particulate materials which may be discharged into the atmosphere. For example, for stationary sources, such as industrial process furnaces and heaters and boilers utilized in electrical generation, the 1974 maximum limit of particulate matter discharge was 0.1 lb/MM BTU of energy produced by a given furnace, heater or boiler. Presently, this limit is 0.03 lb/MM BTU and presumably this limit will be lowered in the future. While there are no present regulations limiting particulate emissions from spark-ignition and compression-ignition engines, proposed standards, scheduled to be effective in 1981 or 1982, limit emissions to 0.6 gram/mile and by 1983 or thereafter to 0.2 gram/mile traveled by the vehicle. Current shortages of petroleum make the problems of the burner or engine manufacturer as well as the fuel manufacturer even more difficult. From the fuel manufacturer's standpoint, it has become necessary to utilize less desirable petroleum sources to produce fuel and to look to other fossil fuel sources, such as coal, shale oil, coal oils and the like to supplement the crude oils presently available. From the equipment manufacturer's standpoint, the standards for stationary source equipment can be met by utilizing scrubbers, precipitators, cyclone separators and the like to clean up the flue gases. However, such equipment cannot be utilized, as a practical matter, in the so-called non-stationary burners, such as compression-ignition and spark-ignition engines. In addition, petroleum shortages have renewed interest in the utilization of the compression-ignition or diesel engine for automotive use, since such engines are considered more economical and are capable of utilizing heavier or less volatile fuels than the ordinary spark-ignition engine. However, as indicated previously such heavier fuels and fuels from non-petroleum sources are more prone to produce exhaust gases containing large amounts of unburned fuels, partially burned fuels, carbon particles and other particulate material.
Since the more exotic cleanup equipment utilized to clean up the flue gases from stationary sources cannot be utilized in the socalled non-stationary engines, it has recently been proposed that filters be utilized on the exhaust from a diesel engine or the like for removing the non-gaseous pollutants from the exhaust. However, the very nature of these non-gaseous pollutants, particularly from low volatility oils, create serious problems in the utilization of conventional filter systems. For example, carbon particles and the like may be as small as 0.1.mu. and accordingly the filter must be designed to have a relatively low permeability so as to screen out these small particles. In addition, the non-gaseous pollutants are often made up of as much as 30 percent of heavy oils. Accordingly, in addition to requiring a low permeability filter there is a tendency for the filter to readily plug due both to the low permeability as well as the nature of the material being filtered out. Replacement of the filter at quite frequent intervals would appear to be necessary. However, this is not a practical solution because of the fact that the volume of such non-gaseous pollutants contained in emissions from low volatility oils and fuels from non-petroleum sources may be as high as 1 to 3 gallons/1000 miles traveled by the vehicle or even higher.
It is therefore an object of the present invention to overcome the above mentioned problems of the prior art.
Another object of the present invention is to provide an improved method and apparatus for the reduction of non-gaseous pollutants in the burning of a fuel.
A further object of the present invention is to provide an improved method and apparatus for the reduction of non-gaseous pollutants in the burning of a fuel having a low volatility.
Still another object of the present invention is to provide an improved method and apparatus for the reduction of non-gaseous pollutants in the burning of fuels from non-petroleum sources.
Another and further object of the present invention is to provide an improved method and apparatus for filtering out non-gaseous pollutants from exhaust gases in the burning of a fuel.
A still further object of the present invention is to provide an improved method and apparatus for filtering non-gaseous pollutants from flue and exhaust gases produced in the burning of a fuel.
A further object of the present invention is to provide an improved method and apparatus for filtering non-gaseous pollutants from exhaust gases of a compression-ignition engine.